In the code to generate standalone functions there’s this:

   if (rcpp_export && has_only_int_args(fun)
        && !fun.body_.is_no_op_statement())
          out << "// [[Rcpp::export]]" << EOL;

So it looks like it will only generate Rcpp::export on functions that have int arguments since
has_only_int_args returns fault if any argument is not of the INT_T type. So 1) I don’t understand
why Rcpp::export is not supposed to appear on doubles functions; and 2) actually a doubles
function I tried to generate does get an Rcpp::export comment prepended to it so I don’t understand
that either. Does anyone know the logic here?

Never mind, found it.